In a wireless cellular telecommunications network, the area covered by the network is divided into an plurality of cells. Each cell is provided with a base station which is able to communicate with mobile stations located in the cell associated with the base station. The mobile stations are able to move from cell to cell. When a mobile station moves from one cell to another, this is referred to as handoff. In this document, the term cell will be used to refer to cells and/or cell sectors.
In current systems, the mobile station is arranged to monitor channels from a number of base stations in the cells neighbouring the cell in which the mobile station is currently located. The mobile station measures the received strength of the signals from the surrounding base stations. Based on this information a decision is made as to whether the current cell is to be changed and if so to which cell. However this method has the disadvantage of not receiving any information relating to, for example, traffic conditions in the neighbouring cells. This means that the mobile station's decision will be based solely on the magnitude of the received signals. Accordingly, the mobile station will not always make the appropriate decision.
A common channel of the neighbouring cell could be continuously monitored and decoded by a mobile station in a different cell in order to obtain information on an adjacent cell. However, this is disadvantageous if a mobile station is in an idle state as it will consume power reducing the battery life. This channel could be the broadcast control channel BCCH.